This blog is about love for snow crabs, but also about snow crab lovin', and as such I feel the need... the need for speed. NO! Sorry, I just kinda slipped into that. No, I feel the need to explain snow crab sexual structures.
First the females: their abdominal flap is wide, almost the entire width of their body when they're mature. This allows them to hold as many fertilized eggs between their abdominal flap and body as possible. Next they have two spermathecae under their abdominal flap, where males deposit spermatophores (capsules of sperm) for the females to use at their leisure when fertilizing eggs. It's said the sperm in the spermathecae are viable for up to 3 years! Storing sperm is a handy way to fertilize subsequent clutches without having to find a male and mate again, especially since mating can be so violent.
Why do females have two spermathecae? Because males have two gonopods (crab penises)!! Yep, it's not just for sharks; snow crab males are cool too. The gonopods are hidden under their abdominal flaps, which are quite skinnier that females' flaps.
two gonopods under the male's adbominal flap
Males will hold the females in an abdomen-to-abdomen position in order to do the deed, then guard the females afterward in case there are any other males around. Once the females extrude their eggs and fertilize them, the males know their job is done, and they go their separate ways.